This invention relates to a high performance patch cord assembly for the high frequency transmission of signals, particularly in the field of telecommunications. More specifically, the invention relates to an assembly that incorporates at least one electrical connector that features a plurality of flat blades as the connection interface for mating with a connecting block that includes a plurality of slotted beams, each pair of opposing beams to receive a respective flat blade.
High frequency transmission systems, particularly those offering Category 5 performance levels, are receiving increasing attention in the telecommunication area. However, to achieve such performance levels requires careful analysis of the total system, i.e. hardware and cabling. That is, the communication system and/or network efficiency is directly dependent upon the integrity of the connector scheme employed. Such connector schemes include, for example, standard interfaces for equipment/user access (outlet connector), transmission means (horizontal and backbone cabling), and administration/distribution points (cross-connect and patching facilities). Regardless of the type or capabilities of the transmission media used for an installation, the integrity of the wiring infrastructure is only as good as the performance of the individual components that bind it together and to the way in which these components are assembled.
Reliability, connection integrity and durability are also important considerations, since wiring life cycles typically span many years. In order to properly address specifications for, and performance of telecommunications connecting hardware, it is important to establish a meaningful and accessible point of reference. The primary reference, considered by many to be the international benchmark for commercially based telecommunications components and installations, is standard EIA/TIA-568-A (TIA-568-A) Commercial Building Telecommunications Wiring Standard. Among the many aspects of telecommunications wiring covered by these standards are connecting hardware design, reliability and transmission performance. Accordingly, the industry has established a common set of test methods and pass/fail criteria on which performance claims and comparative data may be based.
A primary performance criteria for connecting hardware is near-end crosstalk (NEXT), where connector crosstalk is a measure of signal coupling from one pair to another within a connector at various frequencies. Since crosstalk coupling is greatest between transmission segments close to the signal source, near end crosstalk (as opposed to far-end) is generally considered to be the worst case. Although measured values are negative, near-end crosstalk (NEXT) loss is expressed in decibels as a frequency dependent value. The higher the NEXT loss magnitude, the better the crosstalk performance. Near-end crosstalk loss, the more significant problem, may be defined as a measure of signal coupling from one circuit to another within a connector and is derived from swept frequency voltage measurements on short lengths of 100-ohm twisted-pair test leads terminated to the connector under test. A balanced input signal is applied to a disturbing pair of the connector while the induced signal on the disturbed pair is measured at the near-end of the test leads. In other words, NEXT loss is the way of describing the effects of signal coupling causing portions of the signal on one pair to appear on another pair as unwanted noise. In accordance with the standard set forth in EIA/TIA-568-A for Category 5 performance, at a frequency of 100 MHz, the performance must be at least -40 dB.
U.S. Pat. No. 5,226,835 represents a patch cord plug of the general type contemplated by this invention, where the reduced cross-talk of the patented device is achieved through the use of plural pairs of conductors that cross over and are spaced apart. The invention thereof is directed to a plug for interconnecting a pair of wires at its input with a pair of insulation displacement connectors (IDC) at its output. The plug comprises a dielectric housing and a pair of non-insulated conductors within the housing that cross over and are spaced apart from each other. Each conductor comprises a generally flat blade portion for insertion into an IDC at one end, and a terminal for making electrical contact with a wire at the other. A feature thereof is the provision that the conductors are identical to each other, but are reverse-mounted with respect to each other to achieve crossover. While such connector offers improved crosstalk performance, by the use of the conductor crossover scheme, a change is made in the termination sequence which can cause some wiring problems.
The present invention avoids the problems of the wiring sequence associated with the prior art while offering improved performance, particularly at Category 5 levels. The manner by which this performance level is achieved will become apparent in the description which follows, particularly when read in conjunction with the accompanying drawings.